Reverse harvesting sequence of nasoseptal flaps during endoscopic skull base surgery: Technical modification to deal with the severe septal spur

In 2006, a vascularized posteriorly based pedicled nasoseptal flap (NSF) (Hadad-Bassagaisteguy flap) was described as a technique for reconstructing the skull base after endonasal skull base surgery. This flap was shown to markedly reduce the incidence of postoperative cerebrospinal fluid (CSF) leaks in this group of patients. This flap has great utility in reconstructing a wide variety of skull base defects, and is versatile enough to be taken down and re-used (recycled) in revision situations. A subsequent reverse rotation flap from the contralateral side was described to reconstruct the denuded anterior septum left after the harvest of the NSF. This allows for more rapid remucosalization of the remaining septum and reduces the nasal morbidity of these surgeries. In cases of midline pathology, either the left or right NSF can be used to reconstruct the skull base, with the contralateral anterior based septal reverse flap rotated to reconstruct the anterior denuded donor septum. However, in lateralized pathologies where internal carotid artery (ICA) exposure is desirable, it is necessary to utilize the contralateral (to the desired ICA exposure) nasoseptal flap to reconstruct the skull base, with the ipsilateral (to the desired ICA exposure) reverse rotation flap used to reconstruct the septum. The rationale for this is the asymmetric dissection required to identify the vidian neurovascular complex to expose the ICA. Therefore, in these atypical cases, the dissection of the ipsilateral ICA mandates that the flap must be raised from the contralateral side to protect the pedicle (nasoseptal artery), Figure 1. The challenge arises when dissection of a specific ICA is needed requiring the NSF to be raised contralaterally in the presence of a sharp bony spur that risks perforation.